Grinding mill



Sept. 24, 11929. A. E. G. MacCALLUM 1,729,515

GRINDING MILL Filed Nov. 19, 1928 flverz 2 07' ewrtorn Patented 24, 1929 UNITED STATES PATENT OFFICE GRINDING MILL Application filed November 19,1928, Serial No.

This invention relates to roller mills ot the kind used for grinding paint and similar materials and has particular reference to that character of roller mill wherein a grinding bar extends in a direction parallel to the axis of a roll which may be arranged to re ciprccate axially as well as to rotate.

The object of the present invention is to provide means for creating a pressure on the material to be ground to ensure its passage between the grinding elements and to prevent the material to be ground from accumulating in a mass in advance of the grinding bar and failing to pass between the grinding roll and grinding bar, the invention being particularly applicable to mills intended for grinding water paints, pastes, or paints containing a low percentage of oil.

The invention contemplates the employment, in association with a grinding roll, of one or more pilot rolls disposed in advance of the point of engagement of two grinding elements, such pilot roll being of such dimensions and rotating at such speed as to create a pressure in the material under treatment sufficient to force it between the grinding elements.

Reference will now be made to the accompanying drawing which illustrates by way 3 of example a sectional elevation of a construction according to the invention.

In the form illustrated a indicates part of a grinding roll and b a grinding block having its forward edge concaved to conform with and lie in close proximity to the surface of said grinding roll. In advance of the grinding block b is disposed a pilot roll a which rotates in a direction opposite to that of the grinding roll a, and which is actuated in any suitable manner, for example, through gearing from the main power shaft of the mill (not shown). Engaging the pilot roll is a scraping element f formed of spring steel and attached by means of screws 9 to the grinding bar 7). The pilot roll 6 is preferably provided with a grooved, fluted or otherwise serrated surface and it extends parallel to the grinding roll a to which it is equal in length.

A supporting rail 71 extends from end to 320,472, and in Great Britain September 5, 1927.

end of the grinding roll a adjacent the surface of the latter, and the grinding block b is mounted to slide on said bar toward and away from the grinding roll a in order that the space between said block and the grinding roll may be varied and wear between said block and roll may be compensated for. The supporting rail has an arm j extending at substantially a right angle thereto behind the grinding bar 7). A screw-threaded opening is formed in the arm and a screw-threaded spindle is mounted in said opening with its forward end bearing against the rear end of the grinding block b. Said spindle may be actuated by a hand wheel cl mounted on the rear end of same so that, by screwing said spindle in or out, the grinding bar may be adjusted relatively to the grinding roll a.

A side cheek it extends upwardly from each end of the supporting rail 2', and the forward edge of each of said checks is shaped to conform to and lie in close proximity to the surface of the grinding roll a. The pilot roll 0 is journaled at its ends in a block of which the opposite ends are slidable in guideways formed on inner surfaces of the cheeks 7i substantially parallel with the supporting rail 2'. A second opening is formed in the arm of the rail 2' behind the block in which the ends of the pilot roll are journaled and a stud has one end secured to the rear face of said block and its other end formed with screw-threads and extending through said second opening in said arm j. Said block, and with it the pilot roll 0, may be adjusted toward or away from the grinding roll a by adjusting the nuts mounted on the screwthreaded portion of the stud h and engaging the opposite faces of the arm j.

In operation the material under treatmentpasses between the pilot roll 6 and grinding roll a and is carried downwardly by the grinding roll a towards the grinding bar Y) but during its progress downwards the material is picked up in the depressions in the surface of the pilot roll 6 from which it is removed by the scraper blade 7' and accumulates in the space enclosed between the scraper f, the side cheeks of the supporting bar i, the operative surface of the grinding block b and the grinding roll surface a, the proportions and arrangement of the parts being such that more material can enter this space than can pass away between the grinding roll and bar. The pressure thus created on the material acts to force the material between the grinding elements and thus prevents the grinding bar from acting merely to remove the material from the surface of the roll instead of grinding it. The co-operation between the scraper blade 7' and the pilot roll 6 also serves to break up skins, large lumps and other matter which would otherwise accumulate in front of the grinding block b.

I claim 1. A grinding mill, comprising a grinding roll, a rail extending longitudinally of said roll with its forward edge adjacent the surface of the latter, said rail having side cheeks extending upwardly from its ends and a bracket extending upwardly from its rear edge, the forward edges of said side cheeks being curved to conform to and lie close to the surface of said roll, a grinding block supported by said rail and extending longitudinally of said roll, said grinding block having its forward face shaped to conform to and bear against the surface of said grinding roll, a pilot roll ournaled between said side cheeks above said grinding block in spacedrelation to the latter with its surface in close proximity to that of said grinding roll, and a scraper carried by said grinding block and extending between said side cheeks with its edge in engagement with the surface of said pilot roll.

2. A grinding mill, comprising a grinding roll, a rail extending longitudinally of said roll, said rail having side cheeks extending upwardly from its ends adjacent the ends of said grinding roll, a grinding block supported by said rail and extending between the side cheeks of the latter, a pilot roll ournaled between said side cheeks above and in spaced relation to said grinding block, and a scraper mounted between said grinding bar and pilot roll with one of its edges bearing against the latter, the forward edges of said cheeks and of said grinding bar being shaped to conform to and lying in close proximity to the surface of said grinding roll, said side cheeks,.pilot roll and scraper forming with said grinding roll and grinding bar a chamber wherein the material which passes between said pilot roll and grinding roll is compressed and from which it is forced under pressure between said grinding roll and grinding bar.

8. 'A grinding mill according to claim 2, wherein the pilot roll and grinding block are independently adjustable toward and away from the grinding roll.

4. grinding mill accordin to claim 1, wherein the grlnding bar 1s slidable 011 the rail toward and away from the grinding roll and means, including a screw, are carried by the bracket for adjusting the grinding bar relatively to the grinding roll.

5. A grinding mill according to claim 1, wherein guideways are formed on the inner sides of the cheeks substantially parallel with the rail, the pilot roll is journaled at its opposite ends in blocks slidable in said guideways, and means, including a-screw, are associated with said blocks and bracket for adjusting said blocks longitudinally of said guideways.

In testimony whereof I have hereunto set my hand.

ALFRED ERASMUS GEOFFREY MacCAl-LUM. 

